JP5544501B2 - Current sensor - Google Patents

Description

  The present invention relates to a current sensor that measures the magnitude of a current. In particular, the present invention relates to a current sensor in which a decrease in measurement accuracy due to a disturbance magnetic field is suppressed.

  In fields such as motor drive technology in electric vehicles and hybrid cars, a relatively large current is handled, and thus a current sensor capable of measuring a large current in a non-contact manner is required for such applications. As such a current sensor, a system that detects a change in a magnetic field caused by a current to be measured by a magnetic sensor has been put into practical use. A current sensor using a magnetic sensor has a problem in that the measurement accuracy is deteriorated due to the influence of a disturbing magnetic field.

  As a method for suppressing a decrease in measurement accuracy due to the influence of a disturbance magnetic field, for example, a method of canceling the influence of a disturbance magnetic field by providing an MI (Magneto Impedance) element in the opposite direction to the magnetic field generated by the detected current is proposed. (See Patent Document 1).

JP 2001-305163 A

  Incidentally, in addition to the MI element, a GMR (Giant Magneto Resistance) element, a Hall element, or the like can be used for the magnetic sensor used in the above-described current sensor. When a GMR element or the like is used for a current sensor, the influence of a disturbance magnetic field may not be sufficiently suppressed even if the technique described in Patent Document 1 is applied.

  This invention is made | formed in view of this point, and it aims at providing the current sensor which reduced the influence of a disturbance magnetic field and suppressed the fall of the current measurement precision.

  The current sensor of the present invention is arranged around a current line through which a current to be measured flows, detects an induced magnetic field caused by a current flowing through the current line, and has a sub-sensitivity axis in a direction perpendicular to the main sensitivity axis. A first magnetic sensor and a second magnetic sensor, wherein the first magnetic sensor and the second magnetic sensor are arranged with the current line in between, and a main sensitivity axis of the first magnetic sensor The direction is a direction that is not orthogonal to the direction of the induced magnetic field from the current that flows through the current line, and the direction of the main sensitivity axis of the second magnetic sensor is the direction of the induced magnetic field from the current that flows through the current line The first magnetic sensor and the second magnetic sensor are arranged so as to face non-orthogonal directions, the main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are directed in the same direction, and the first magnetic sensor and the second magnetic sensor. Each secondary sensitivity axis Are arranged so as to face the same direction, or the respective main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are directed in opposite directions, and the first magnetic sensor and the second magnetic sensor Each of the magnetic sensors is arranged so that the sub-sensitivity axis directions are opposite to each other.

  According to this configuration, the primary sensitivity axis directions of the first magnetic sensor and the second magnetic sensor face the same direction, and the secondary sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are the same. Since the direction is directed, the influence of the disturbance magnetic field appears equally in the output of the first magnetic sensor and the output of the second magnetic sensor. For this reason, by taking the difference between the output of the first magnetic sensor and the output of the second magnetic sensor, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in current measurement accuracy. Alternatively, the primary sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are opposite directions, and the secondary sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are opposite directions. Therefore, the influence of the disturbance magnetic field appears oppositely between the output of the first magnetic sensor and the output of the second magnetic sensor. For this reason, by taking the sum of the output of the first magnetic sensor and the output of the second magnetic sensor, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the reduction in current measurement accuracy.

  In the current sensor of the present invention, the main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are in the same direction, and the output of the first magnetic sensor and the output of the second magnetic sensor. An arithmetic device that takes the difference between the two may be included.

  In the current sensor of the present invention, the main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are opposite to each other, and the output of the first magnetic sensor and the output of the second magnetic sensor. An arithmetic device that takes the sum of the above may be included.

  The current sensor according to the present invention includes: a first circuit board on which the first magnetic sensor is disposed on a placement surface; and a second circuit board on which the second magnetic sensor is disposed on a placement surface. The arrangement surface of the first circuit board and the arrangement surface of the second circuit board may be arranged to face each other across the current line.

  According to this configuration, since the first magnetic sensor and the second magnetic sensor are arranged symmetrically with respect to the current line, the distance between the current line and the first magnetic sensor, and the current line and the second magnetic sensor. It is easy to make the distance from the sensor uniform. For this reason, it is possible to sufficiently improve the current measurement accuracy. In addition, since there is no circuit board between the current line and the first magnetic sensor and between the current line and the second magnetic sensor, the distance between the current line and the first magnetic sensor, and the current line The distance from the second magnetic sensor can be reduced. For this reason, it is possible to increase the sensor output and sufficiently increase the current measurement accuracy.

  The current sensor according to the present invention includes: a first circuit board on which the first magnetic sensor is disposed on a placement surface; and a second circuit board on which the second magnetic sensor is disposed on a placement surface. The surface of the first circuit board opposite to the arrangement surface and the surface of the second circuit board opposite to the arrangement surface may be arranged to face each other across the current line.

  According to this configuration, since the first magnetic sensor and the second magnetic sensor are arranged symmetrically with respect to the current line, the distance between the current line and the first magnetic sensor, and the current line and the second magnetic sensor. It is easy to make the distance from the sensor uniform. For this reason, it is possible to sufficiently improve the current measurement accuracy.

  In the current sensor of the present invention, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor have a mirror image relationship. good.

  In the current sensor of the present invention, when the first magnetic sensor and the second magnetic sensor are viewed from the surface side, an angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction of the first magnetic sensor; The angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction of the second magnetic sensor is equal, and the surface of the first magnetic sensor faces the arrangement surface of the first circuit board. Thus, the second magnetic sensor may be arranged on the first circuit board, and the second magnetic sensor may be arranged on the second circuit board so that the back surface thereof faces the arrangement surface of the second circuit board.

  According to this configuration, since two magnetic sensors having the same configuration can be used, it is possible to sufficiently cancel the influence of the disturbance magnetic field and suppress a decrease in current measurement accuracy.

  The current sensor according to the present invention includes a first circuit board on which the first magnetic sensor is disposed on the placement surface, and a second circuit board on which the second magnetic sensor is disposed on the placement surface, The arrangement surface of the first circuit board and the surface of the second circuit board opposite to the arrangement surface may be arranged to face each other with the current line interposed therebetween.

  According to this configuration, since the mounting pattern of the first magnetic sensor on the first circuit board is the same as the mounting pattern of the second magnetic sensor on the second circuit board, the magnetic sensor is mounted in the same process. A current sensor can be configured using the circuit board thus formed. For this reason, it becomes possible to arrange the characteristics of the magnetic sensor and the circuit board at a low cost.

  In the current sensor of the present invention, a spacer is disposed between the current line and the first magnetic sensor, or between the current line and the first circuit board, whereby the current line and the first magnetic sensor are arranged. The distance between the magnetic sensor and the distance between the current line and the second magnetic sensor may be the same.

  According to this configuration, the distance between the current line and the first magnetic sensor and the distance between the current line and the second magnetic sensor can be easily made uniform by the spacer. For this reason, it is possible to sufficiently improve the current measurement accuracy.

  In the current sensor of the present invention, the first magnetic sensor and the second magnetic sensor may be elements having the same structure manufactured using the same wafer.

  According to this configuration, since two magnetic sensors having the same sensitivity on the main sensitivity axis and the secondary sensitivity axis can be used, it is possible to sufficiently cancel the influence of the disturbance magnetic field and suppress a decrease in current measurement accuracy. is there.

  In the current sensor of the present invention, each of the first magnetic sensor and the second magnetic sensor is a magnetic sensor using a magnetoresistive effect element, and the second sensitivity axis direction of the first magnetic sensor and the second magnetic sensor are The sub-sensitivity axis direction of the magnetic sensor may be the direction of the hard bias of each magnetoresistive element.

  According to this configuration, since the sub-sensitivity axis direction is controlled by the direction of the hard bias, the sensitivity characteristics in the sub-sensitivity axis direction of the GMR element are aligned. Thereby, it is possible to cancel the influence of the disturbance magnetic field appearing in the auxiliary sensitivity axis direction with high accuracy.

  In the current sensor of the present invention, the first magnetic sensor and the second magnetic sensor may be a magnetic sensor using a Hall element with a magnetic converging plate.

  In the current sensor of the present invention, the main sensitivity axis direction of the first magnetic sensor is oriented in a direction parallel to the induced magnetic field from the current flowing through the current line, and the main sensitivity axis direction of the second magnetic sensor is The direction may be parallel to the direction of the induced magnetic field from the current flowing through the current line.

  In the current sensor of the present invention, the main sensitivity axis direction of the first magnetic sensor faces a direction not parallel to the induced magnetic field from the current flowing through the current line, and the main sensitivity axis direction of the second magnetic sensor May be directed in a direction not parallel to the direction of the induced magnetic field from the current flowing through the current line.

  According to the present invention, it is possible to provide a current sensor that reduces the influence of a disturbance magnetic field and suppresses a decrease in current measurement accuracy.

4 is a schematic diagram illustrating a configuration example of a current sensor according to Embodiment 1. FIG. FIG. 3 is a block diagram illustrating a circuit configuration example of the current sensor according to the first embodiment. 5 is a schematic diagram illustrating an example of a method for manufacturing the current sensor according to Embodiment 1. FIG. It is a schematic diagram which shows the structural example of the conventional current sensor. 6 is a schematic diagram illustrating a configuration example of a current sensor according to Embodiment 2. FIG. 10 is a schematic diagram illustrating an example of a method of manufacturing a current sensor according to Embodiment 2. FIG. 6 is a schematic diagram illustrating a configuration example of a current sensor according to Embodiment 3. FIG. 10 is a schematic diagram illustrating an example of a method for manufacturing a current sensor according to Embodiment 3. FIG. 6 is a schematic diagram illustrating a configuration example of a current sensor according to Embodiment 4. FIG. FIG. 10 is a schematic diagram illustrating an example of a method for manufacturing a current sensor according to a fourth embodiment. FIG. 10 is a schematic diagram illustrating a configuration example of a current sensor according to a fifth embodiment. FIG. 10 is a schematic diagram illustrating an example of a method for manufacturing a current sensor according to a fifth embodiment. FIG. 10 is a schematic diagram showing a modification of the current sensor according to the fifth embodiment. FIG. 10 is a schematic diagram showing the structure of a GMR element according to a sixth embodiment. It is a graph which shows the resistance value of the GMR element at the time of applying a magnetic field to the subsensitivity axis direction. FIG. 10 is a schematic diagram illustrating a configuration example of a current sensor according to a seventh embodiment. FIG. 10 is a schematic diagram illustrating another configuration example of the current sensor according to the seventh embodiment.

  The present inventor has found that, in a current sensor using a magnetic sensor including a GMR element or the like, a factor that cannot sufficiently suppress the influence of a disturbance magnetic field is that the sensitivity is in a direction perpendicular to the sensitivity axis. For example, in a magnetic sensor using a GMR element, the sensitivity in the direction orthogonal to the sensitivity axis may be about several tens of percent of the sensitivity in the sensitivity axis direction. Thus, when using a magnetic sensor having sensitivity also in the direction orthogonal to the sensitivity axis, simply directing the direction of the sensitivity axis (hereinafter referred to as the main sensitivity axis direction) to the direction of the induced magnetic field can take a difference in output. The influence of the disturbance magnetic field cannot be removed sufficiently. This is because the influence of the disturbance magnetic field appearing in the direction orthogonal to the main sensitivity axis direction (hereinafter referred to as the secondary sensitivity axis direction) cannot be canceled only by the control in the main sensitivity axis direction.

  Based on such knowledge, the present inventors have come up with the idea of canceling the influence of a disturbance magnetic field appearing in the sub-sensitivity axis direction by controlling the directions of the sub-sensitivity axes of the two magnetic sensors. That is, the essence of the present invention is that a current sensor of a type that eliminates the influence of a disturbance magnetic field by calculating (difference or summation) the outputs of two magnetic sensors, the two magnetic sensors are connected to their respective sub-sensitivity axes. It is intended to reduce the influence of the disturbance magnetic field and suppress the decrease in current measurement accuracy by arranging the sub-sensitivity axis directions so that they are in the same direction or in opposite directions. is there. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
In the present embodiment, an example of the current sensor 1 of the present invention will be described. FIG. 1 is a schematic diagram showing a current sensor 1 of the present embodiment. FIG. 1A is a perspective view schematically showing the configuration of the current sensor 1 and its periphery, and FIG. 1B is a plan view of the current sensor 1 as viewed from the lower left direction (front) of FIG. 1A. In the following, in the perspective view, the lower left direction of the paper is called the front, the upper right direction of the paper is the rear, the left direction of the paper is the left, the right direction of the paper is the right, the upper direction of the paper is the upper,

  In FIG. 1, a solid arrow given to the current line 11 indicates the direction of current flowing through the current line 11. That is, in FIG. 1, the direction of the measured current I flowing through the current line 11 is rightward. Solid arrows provided around the current line 11 indicate the direction of the induced magnetic field A generated by the current I to be measured. In FIG. 1, solid arrows 14a and 14b applied to the first magnetic sensor 12a and the second magnetic sensor 12b represent the respective main sensitivity axis directions, and broken arrows 15a and 15b represent the respective main sensitivity axis directions. Represents the secondary sensitivity axis direction. Here, the “main sensitivity axis” refers to the axis that faces the direction in which the sensitivity of the magnetic sensor is maximized, and the “sub sensitivity axis” has the highest sensitivity in the direction orthogonal to the main sensitivity axis. An axis that points in the direction. In addition, the front surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b are marked with a circle to facilitate the front / back identification. Black circles indicate that the surface is facing up, and white circles indicate that the surface is facing down.

  As shown in FIG. 1, the current sensor 1 includes a first magnetic sensor 12a and a second magnetic sensor 12b arranged around a current line 11 through which a current to be measured flows. Here, the current line 11 may be in any form as long as it is a component capable of guiding current. For example, the current line 11 includes a non-linear shape such as a plate-like conductive member or a thin-film conductive member (conductive pattern). The current line 11 is treated as not being a component of the current sensor 1.

  In addition to the first magnetic sensor 12a and the second magnetic sensor 12b, the current sensor 1 includes a first circuit board 13a on which the first magnetic sensor 12a is disposed and a second magnetic sensor 12b. Circuit board 13b. Moreover, the calculation apparatus 16 (FIG. 2) which calculates the output of the 1st magnetic sensor 12a and the output of the 2nd magnetic sensor 12b is included.

  The first magnetic sensor 12a and the second magnetic sensor 12b are not particularly limited as long as they can detect magnetism and have a secondary sensitivity axis in a direction orthogonal to the main sensitivity axis. For example, in a magnetic sensor using a magnetoresistive effect element such as a GMR (Giant Magneto Resistance) element or a TMR (Tunnel Magneto Resistance) element that uses a hard bias to smooth the sensitivity, there is a secondary sensitivity axis. Further, even in the Hall element, when a magnetic field sensitivity axis is provided in the element surface using a magnetic flux collector, a secondary sensitivity axis exists. For this reason, a GMR element, a TMR element, a Hall element with a magnetic converging plate, or the like can be used for the first magnetic sensor 12a and the second magnetic sensor 12b.

  In the current sensor 1 shown in FIG. 1, the first magnetic sensor 12 a and the second magnetic sensor 12 b can obtain substantially reversed phase outputs by the induced magnetic field A from the current I to be measured flowing through the current line 11. As shown in FIG. For example, in FIG. 1, the current line 11 is sandwiched between the first magnetic sensor 12a and the second magnetic sensor 12b, and the main lines of the first magnetic sensor 12a and the second magnetic sensor 12b are used. The sensitivity axis direction (arrows 14a and 14b) is arranged so as to face a direction perpendicular to the direction in which the current line 11 extends. More specifically, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the second magnetic sensor 12b The direction of the main sensitivity axis (arrow 14b) faces in the opposite direction to the direction of the induced magnetic field A from the current I to be measured flowing through the current line 11, and each of the first magnetic sensor 12a and the second magnetic sensor 12b. The main sensitivity axis directions are arranged in the same direction. In addition, the sub-sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are arranged in the same direction. Further, the first magnetic sensor 12 a and the second magnetic sensor 12 b are arranged so that the surfaces thereof face the direction of the current line 11.

  In the current sensor 1 shown in FIG. 1, one main sensitivity axis direction of the first magnetic sensor 12 a and the second magnetic sensor 12 b indicates the direction of the induced magnetic field A from the measured current I flowing through the current line 11. The direction of the other main sensitivity axis is opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11, so that the influence of the induced magnetic field A affects the first magnetic sensor 12a and the first magnetic sensor 12a. 2 appears as an output signal of substantially opposite phase from the second magnetic sensor 12b. Further, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b face the same direction, and the sub sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are the same. Since the direction is directed, the influence of the disturbance magnetic field appears equally in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the difference between the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy. Note that the substantially reverse phase output signal refers to an output signal having an inversion relationship excluding noise components and the like. However, since it is sufficient that the relationship is such that current measurement can be performed with a desired accuracy, it is not required that the value be strictly reversed.

  In the current sensor 1 shown in FIG. 1, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor 12a and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor 12b are mirror images. There is a relationship. That is, when the first magnetic sensor 12a and the second magnetic sensor 12a are viewed from the surface side, the sub-sensitivity axis direction of the first magnetic sensor 12a and the second magnetic sensor are based on the respective main sensitivity axis directions. This is in a direction opposite to the sub-sensitivity axis direction of 12a.

  FIG. 2 is a block diagram according to the circuit configuration of the current sensor 1. As shown in FIG. 2, the current sensor 1 includes an arithmetic device 16 connected to the output terminals of the first magnetic sensor 12 a and the second magnetic sensor 12 b. Here, the arithmetic device 16 has a function of calculating a difference between the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, when a current flows through the current line 11 and an induction magnetic field is generated around the current line 11, an output signal corresponding to the current is output from the first magnetic sensor 12a and the second magnetic sensor 12b. Receiving the output signal, the arithmetic unit 16 can calculate and output the difference between the two output signals. By taking the difference between the two output signals in this way, the influence of the disturbance magnetic field can be canceled and the current measurement accuracy can be improved. Note that the function of the arithmetic device 16 may be realized by hardware or software.

  FIG. 3 is a schematic diagram showing an example of a method for manufacturing the current sensor 1 described above. As shown in FIG. 3A, first, a first magnetic sensor 12a and a second magnetic sensor 12b are prepared. In FIG. 3A, the primary sensitivity axis direction of the first magnetic sensor 12a faces forward, and the secondary sensitivity axis direction faces left. In addition, the main sensitivity axis direction of the second magnetic sensor 12b faces forward, and the sub sensitivity axis direction faces right. That is, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor 12a and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor 12b are in a mirror image relationship. Here, the main surfaces on the upper side (GMR element side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The main surfaces on the lower side (substrate side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the back surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The relationship between the front and back may be reversed.

  Next, as shown in FIG. 3B, the first magnetic sensor 12a is arranged on the magnetic sensor arrangement surface (hereinafter, arrangement surface) of the first circuit board 13a, and the second magnetic sensor 12b is arranged in the second circuit. It arrange | positions on the arrangement | positioning surface of the board | substrate 13b. That is, the first magnetic sensor 12a is arranged such that the back surface of the first magnetic sensor 12a faces the arrangement surface of the first circuit board 13a, and the back surface of the second magnetic sensor 12b and the second circuit board 13b. The second magnetic sensor 12b is arranged so as to face the arrangement surface. Here, the arrangement surface (magnetic sensor arrangement surface) is a main surface provided in the first circuit board 13a or the second circuit board 13b, and the arrangement of the first magnetic sensor 12a or the second magnetic sensor 12b. Refers to the main surface. As a result, as shown in FIG. 3B, the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b are both directed upward, and the first magnetic sensor 12a and the second magnetic sensor 12b When the respective primary sensitivity axis directions (arrows 14a and 14b) are directed in the same direction, the respective secondary sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other. Turn to the direction.

  After that, as shown in FIG. 3C, the first circuit board 13a and the second circuit board 13b face each other with the current line 11 therebetween so that the first circuit board 13a and the second circuit board 13b face each other. A circuit board 13a and a second circuit board 13b are arranged. Thereby, the surface of the first magnetic sensor 12a and the surface of the second magnetic sensor 12b face each other with the current line 11 in between. Such an arrangement can be obtained, for example, by rotating the set of the first magnetic sensor 12a and the first circuit board 13a with respect to the set of the second magnetic sensor 12b and the second circuit board 13b. it can.

  In the current sensor 1 obtained by the method shown in FIG. 3, since the first magnetic sensor 12a and the second magnetic sensor 12b are arranged symmetrically with respect to the current line 11, the current line 11 and the first magnetic sensor are arranged. It becomes easy to make the distance to 12a and the distance between the current line 11 and the second magnetic sensor 12b uniform. Thereby, since a disturbance magnetic field can be canceled appropriately, the current measurement accuracy can be sufficiently increased. Moreover, since there is no circuit board between the current line 11 and the first magnetic sensor 12a and between the current line 11 and the second magnetic sensor 12b, the current line 11 and the first magnetic sensor 12a The distance and the distance between the current line 11 and the second magnetic sensor 12b can be reduced. For this reason, it is possible to increase the sensor output and sufficiently increase the current measurement accuracy.

  As described above, the current sensor 1 according to the present embodiment reduces the influence of the disturbance magnetic field and suppresses the decrease in current measurement accuracy, for example, compared with the current sensor 2 shown in FIG. it can. This is because in the current sensor 1 according to the present embodiment, the first magnetic sensor 12a and the second magnetic sensor 12b are arranged so that the sub-sensitivity axis direction faces a direction in which the disturbance magnetic field can be appropriately canceled. It is.

  In FIG. 1, the main sensitivity axis direction of the first magnetic sensor 12 a faces the direction of the induced magnetic field from the current flowing through the current line 11, and the main sensitivity axis direction of the second magnetic sensor 12 b is the current line 11. The case where the direction of the induced magnetic field from the flowing current is opposite to the direction of the induced magnetic field has been described as an example, but the configuration of the current sensor 1 according to the present embodiment is not limited to this. The direction of the main sensitivity axis of the first magnetic sensor 12a is opposite to the direction of the induced magnetic field from the current flowing through the current line 11, and the direction of the main sensitivity axis of the second magnetic sensor 12b is through the current line 11. You may face the direction of the induction magnetic field from the flowing electric current.

  In addition, this embodiment can be implemented in combination with any of the structures described in the other embodiments as appropriate.

(Embodiment 2)
In the present embodiment, another example of the current sensor 1 of the present invention will be described. FIG. 5 is a schematic diagram showing the current sensor 1 of the present embodiment. 5A is a perspective view schematically showing the configuration of the current sensor 1 and its surroundings, and FIG. 5B is a plan view of the current sensor 1 as viewed from the lower left direction (front) of FIG. 5A.

  As shown in FIG. 5, the current sensor 1 according to the present embodiment includes a first magnetic sensor 12a and a second magnetic sensor 12b disposed around the current line 11, and includes the first magnetic sensor 12a. Includes a first circuit board 13a on which is disposed and a second circuit board 13b on which the second magnetic sensor 12b is disposed. The current sensor 1 includes an arithmetic device that calculates the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. In this respect, the current sensor 1 shown in FIG. 5 and the current sensor 1 shown in FIG. 1 are common. The difference between the current sensor 1 shown in FIG. 5 and the current sensor 1 shown in FIG. 1 is in the directions of the primary sensitivity axis direction and the secondary sensitivity axis direction of the first magnetic sensor 12a and the second magnetic sensor 12b.

  In the current sensor 1 shown in FIG. 5, the first magnetic sensor 12 a and the second magnetic sensor 12 b can obtain substantially in-phase outputs by the induced magnetic field A from the measured current I flowing through the current line 11. Are arranged around the current line 11. More specifically, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the second magnetic sensor 12b The main sensitivity axis direction (arrow 14b) faces the direction of the induced magnetic field A from the current I to be measured flowing through the current line 11, and the respective main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b. Are arranged in the opposite direction. The sub-sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are arranged so as to be opposite to each other. Further, the first magnetic sensor 12 a and the second magnetic sensor 12 b are arranged so that the surfaces thereof face the direction of the current line 11.

  In the current sensor 1 having the configuration shown in FIG. 5, the induced magnetic field A from the current I to be measured in which the main sensitivity axis directions of the first magnetic sensor 12 a and the second magnetic sensor 12 b both flow through the current line 11. Therefore, the influence of the induced magnetic field A appears as an output signal of substantially the same phase of the first magnetic sensor 12a and the second magnetic sensor 12b. Further, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other, and the sub sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are respectively opposite. Are directed in opposite directions, the influence of the disturbance magnetic field appears in reverse in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the sum of the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy. Note that the substantially in-phase output signal means an equivalent output signal excluding noise components and the like. However, since it is sufficient if the relationship is such that current measurement can be performed with desired accuracy, it is not required that the values be exactly the same. In the current sensor 1 shown in FIG. 5, the arithmetic unit has a function of calculating the sum of the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b.

  In the current sensor 1 shown in FIG. 5, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor 12a and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor 12b are mirror images. There is a relationship. That is, when the first magnetic sensor 12a and the second magnetic sensor 12a are viewed from the surface side, the sub-sensitivity axis direction of the first magnetic sensor 12a and the second magnetic sensor are based on the respective main sensitivity axis directions. This is in a direction opposite to the sub-sensitivity axis direction of 12a.

  FIG. 6 is a schematic diagram illustrating an example of a method for manufacturing the current sensor 1 according to the present embodiment. As shown in FIG. 6A, first, a first magnetic sensor 12a and a second magnetic sensor 12b are prepared. In FIG. 6A, the primary sensitivity axis direction of the first magnetic sensor 12a faces forward, and the secondary sensitivity axis direction faces left. Further, the main sensitivity axis direction of the second magnetic sensor 12b is facing forward, and the sub sensitivity axis direction is rightward. That is, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor 12a and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor 12b are in a mirror image relationship. Here, the main surfaces on the upper side (GMR element side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The main surfaces on the lower side (substrate side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the back surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The relationship between the front and back may be reversed.

Next, as shown in FIG. 6B, the first magnetic sensor 12a is arranged on the arrangement surface of the first circuit board 13a, and the second magnetic sensor 12b is arranged on the arrangement surface of the second circuit board 13b. . That is, the first magnetic sensor 12a is arranged such that the back surface of the first magnetic sensor 12a faces the arrangement surface of the first circuit board 13a, and the back surface of the second magnetic sensor 12b and the second circuit board 13b. The second magnetic sensor 12b is arranged so as to face the arrangement surface. As a result, as shown in FIG. 6B, the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b face up, and the first magnetic sensor 12a and the second magnetic sensor 12b When the respective primary sensitivity axis directions (arrows 14a and 14b) are directed in the same direction, the respective secondary sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other. Turn to the direction. In FIG. 6B, the second magnetic sensor 12b and the second circuit board 13b are shown rotated by 180 ° in the arrangement plane direction.

  Thereafter, as shown in FIG. 6C, the first circuit board 13a and the second circuit board 13b face each other around the current line 11 so that the first circuit board 13a and the second circuit board 13b face each other. A circuit board 13a and a second circuit board 13b are arranged. Thereby, the surface of the first magnetic sensor 12a and the surface of the second magnetic sensor 12b face each other with the current line 11 in between. Such an arrangement can be obtained, for example, by rotating the set of the first magnetic sensor 12a and the first circuit board 13a with respect to the set of the second magnetic sensor 12b and the second circuit board 13b. it can.

  In the current sensor 1 obtained by the method shown in FIG. 6, since the first magnetic sensor 12a and the second magnetic sensor 12b are arranged symmetrically with respect to the current line 11, the current line 11 and the first magnetic sensor are arranged. It becomes easy to make the distance to 12a and the distance between the current line 11 and the second magnetic sensor 12b uniform. Thereby, since a disturbance magnetic field can be canceled appropriately, the current measurement accuracy can be sufficiently increased. Moreover, since there is no circuit board between the current line 11 and the first magnetic sensor 12a and between the current line 11 and the second magnetic sensor 12b, the current line 11 and the first magnetic sensor 12a The distance and the distance between the current line 11 and the second magnetic sensor 12b can be reduced. For this reason, it is possible to increase the sensor output and sufficiently increase the current measurement accuracy.

  As described above, the current sensor 1 according to the present embodiment can reduce the influence of a disturbance magnetic field and suppress a decrease in current measurement accuracy. This is because in the current sensor 1 according to the present embodiment, the first magnetic sensor 12a and the second magnetic sensor 12b are arranged so that the sub-sensitivity axis direction faces a direction in which the disturbance magnetic field can be appropriately canceled. It is.

  5 and 6, the main sensitivity axis directions of the first magnetic sensor 12 a and the second magnetic sensor 12 b are the directions of the induced magnetic field A from the current I to be measured that flows through the current line 11. However, the configuration of the current sensor 1 according to the present embodiment is not limited to this. Even if the main sensitivity axis directions of the first magnetic sensor 12 a and the second magnetic sensor 12 b are both opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11. good.

  In addition, this embodiment can be implemented in combination with any of the structures described in the other embodiments as appropriate.

(Embodiment 3)
In the present embodiment, another example of the current sensor 1 of the present invention will be described. FIG. 7 is a schematic diagram showing the current sensor 1 of the present embodiment. 7A is a perspective view schematically showing the configuration of the current sensor 1 and its periphery, and FIG. 7B is a plan view of the current sensor 1 as viewed from the lower left direction (front) of FIG. 7A.

  As shown in FIG. 7, the current sensor 1 according to the present embodiment includes a first magnetic sensor 12a and a second magnetic sensor 12b disposed around the current line 11, and includes the first magnetic sensor 12a. Includes a first circuit board 13a on which is disposed and a second circuit board 13b on which the second magnetic sensor 12b is disposed. The current sensor 1 includes an arithmetic device that calculates the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. In this respect, the current sensor 1 shown in FIG. 7 and the current sensor 1 shown in FIG. 1 are common. The difference between the current sensor 1 shown in FIG. 7 and the current sensor 1 shown in FIG. 1 is that the first magnetic sensor 12a and the second magnetic sensor 12b, and the first circuit board 13a and the second circuit board 13b. And the positional relationship. That is, in the current sensor 1 according to the present embodiment, the surface opposite to the arrangement surface of the first circuit board 13a and the surface opposite to the arrangement surface of the second circuit board 13b are connected to the current line 11. The first circuit board 13a and the second circuit board 13b are arranged on the current line side with respect to the first magnetic sensor 12a and the second magnetic sensor 12b.

  In the current sensor 1 shown in FIG. 7, the first magnetic sensor 12 a and the second magnetic sensor 12 b are current lines so that a substantially reverse phase output can be obtained by the induced magnetic field from the current flowing through the current line 11. 11 is arranged around. More specifically, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the second magnetic sensor 12b The direction of the main sensitivity axis (arrow 14b) faces in the opposite direction to the direction of the induced magnetic field A from the current I to be measured flowing through the current line 11, and each of the first magnetic sensor 12a and the second magnetic sensor 12b. The main sensitivity axis directions are arranged in the same direction. In addition, the sub-sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are arranged in the same direction. Further, the first magnetic sensor 12 a and the second magnetic sensor 12 b are arranged so that the back surfaces thereof face the direction of the current lines 11.

  In the current sensor 1 having the configuration shown in FIG. 7, the direction of the induced magnetic field A from the current I to be measured whose one main sensitivity axis direction of the first magnetic sensor 12 a and the second magnetic sensor 12 b flows through the current line 11. Since the other main sensitivity axis direction is directed in the opposite direction to the induced magnetic field A from the current I to be measured flowing through the current line 11, the influence of the induced magnetic field A is affected by the first magnetic sensor 12a. And appears as an output signal of substantially opposite phase from the second magnetic sensor 12b. Further, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b face the same direction, and the sub sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are the same. Since the direction is directed, the influence of the disturbance magnetic field appears equally in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the difference between the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy.

  In the current sensor 1 shown in FIG. 7, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor 12a and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor 12b are mirror images. There is a relationship. That is, when the first magnetic sensor 12a and the second magnetic sensor 12a are viewed from the surface side, the sub-sensitivity axis direction of the first magnetic sensor 12a and the second magnetic sensor are based on the respective main sensitivity axis directions. This is in a direction opposite to the sub-sensitivity axis direction of 12a.

  FIG. 8 is a schematic diagram illustrating an example of a method for manufacturing the current sensor 1 according to the present embodiment. As shown in FIG. 8A, first, a first magnetic sensor 12a and a second magnetic sensor 12b are prepared. In FIG. 8A, the primary sensitivity axis direction of the first magnetic sensor 12a faces forward, and the secondary sensitivity axis direction faces right. In addition, the main sensitivity axis direction of the second magnetic sensor 12b faces forward, and the sub sensitivity axis direction faces left. That is, the main sensitivity axis direction and the sub sensitivity axis direction of the first magnetic sensor 12a and the main sensitivity axis direction and the sub sensitivity axis direction of the second magnetic sensor 12b are in a mirror image relationship. Here, the main surfaces on the upper side (GMR element side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The main surfaces on the lower side (substrate side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the back surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The relationship between the front and back may be reversed.

  Next, as shown in FIG. 8B, the first magnetic sensor 12a is arranged on the arrangement surface of the first circuit board 13a, and the second magnetic sensor 12b is arranged on the arrangement surface of the second circuit board 13b. . That is, the first magnetic sensor 12a is arranged such that the back surface of the first magnetic sensor 12a faces the arrangement surface of the first circuit board 13a, and the back surface of the second magnetic sensor 12b and the second circuit board 13b. The second magnetic sensor 12b is arranged so as to face the arrangement surface. Accordingly, as shown in FIG. 8B, the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b are both directed upward, and the first magnetic sensor 12a and the second magnetic sensor 12b When the respective primary sensitivity axis directions (arrows 14a and 14b) are directed in the same direction, the respective secondary sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other. Turn to the direction.

  Thereafter, as shown in FIG. 8C, the surface opposite to the arrangement surface of the first circuit board 13a and the surface opposite to the arrangement surface of the second circuit board 13b face each other across the current line 11. In addition, the first circuit board 13 a and the second circuit board 13 b are arranged around the current line 11. That is, the first circuit board 13a and the second circuit board 13b are arranged closer to the current line than the first magnetic sensor 12a and the second magnetic sensor 12b. Such an arrangement can be obtained, for example, by rotating the set of the second magnetic sensor 12b and the second circuit board 13b with respect to the set of the first magnetic sensor 12a and the first circuit board 13a. it can.

  In the current sensor 1 obtained by the method shown in FIG. 8, since the first magnetic sensor 12a and the second magnetic sensor 12b are arranged symmetrically with respect to the current line 11, the current line 11 and the first magnetic sensor are arranged. It becomes easy to make the distance to 12a and the distance between the current line 11 and the second magnetic sensor 12b uniform. Thereby, since a disturbance magnetic field can be canceled appropriately, the current measurement accuracy can be sufficiently increased.

  As described above, the current sensor 1 according to the present embodiment can reduce the influence of a disturbance magnetic field and suppress a decrease in current measurement accuracy. This is because in the current sensor 1 according to the present embodiment, the first magnetic sensor 12a and the second magnetic sensor 12b are arranged so that the sub-sensitivity axis direction faces a direction in which the disturbance magnetic field can be appropriately canceled. It is.

  7 and 8, the main sensitivity axis direction of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the main magnetic sensor 12b has a main sensitivity axis direction. The case where the sensitivity axis direction is in the direction opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11 is taken as an example, but the configuration of the current sensor 1 according to the present embodiment is as follows. It is not limited to this. The direction of the main sensitivity axis of the first magnetic sensor 12a is opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the direction of the main sensitivity axis of the second magnetic sensor 12b is the current. The direction of the induced magnetic field A from the measured current I flowing through the line 11 may be directed.

  7 and 8, the configuration for canceling the disturbance magnetic field by taking the output difference has been described, but the configuration of the current sensor 1 according to the present embodiment is not limited to this. A configuration may be adopted in which the disturbance magnetic field is canceled by taking the sum of outputs. In this case, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are both the direction of the induced magnetic field A from the measured current I flowing through the current line 11 or the direction of the induced magnetic field A. It suffices that the sub-sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other in opposite directions.

  In addition, this embodiment can be implemented in combination with any of the structures described in the other embodiments as appropriate.

(Embodiment 4)
In the present embodiment, another example of the current sensor 1 of the present invention will be described. FIG. 9 is a schematic diagram showing the current sensor 1 of the present embodiment. FIG. 9A is a perspective view schematically showing the configuration of the current sensor 1 and its periphery, and FIG. 9B is a plan view of the current sensor 1 as viewed from the lower left direction (front) of FIG. 9A.

  As shown in FIG. 9, the current sensor 1 according to the present embodiment includes a first magnetic sensor 12a and a second magnetic sensor 12b arranged around the current line 11, and includes the first magnetic sensor 12a. Includes a first circuit board 13a on which is disposed and a second circuit board 13b on which the second magnetic sensor 12b is disposed. The current sensor 1 includes an arithmetic device that calculates the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. In this respect, the current sensor 1 shown in FIG. 9 and the current sensor 1 shown in FIG. 1 are common. The difference between the current sensor 1 shown in FIG. 9 and the current sensor 1 shown in FIG. 1 is that the first magnetic sensor 12a and the second magnetic sensor 12b, and the first circuit board 13a and the second circuit board 13b. And the positional relationship. That is, in the current sensor 1 according to the present embodiment, the surface of the first magnetic sensor 12a is disposed so as to face the surface of the first circuit board 13a, and the back surface of the second magnetic sensor 12b is the first. It arrange | positions so that the arrangement surface of 2 circuit board 13b may be opposed. In addition, magnetic sensors having the same configuration are used as the first magnetic sensor 12a and the second magnetic sensor 12b. Therefore, when the first magnetic sensor 12a and the second magnetic sensor 12b are viewed from the surface side, the angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction of the first magnetic sensor 12a, The angle formed by the auxiliary sensitivity axis direction with respect to the main sensitivity axis direction of the magnetic sensor 12b is substantially equal. Here, it is desirable that the first magnetic sensor 12a and the second magnetic sensor 12b include elements having the same structure manufactured using the same wafer. This is because in such a magnetic sensor, the sensitivity of the main sensitivity axis and the secondary sensitivity axis can be made equal, so that the influence of the disturbance magnetic field can be easily canceled.

  In the current sensor 1 shown in FIG. 9, the first magnetic sensor 12 a and the second magnetic sensor 12 b can obtain substantially reverse phase outputs by the induced magnetic field A from the current I to be measured flowing through the current line 11. As shown in FIG. More specifically, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the second magnetic sensor 12b The direction of the main sensitivity axis (arrow 14b) faces in the opposite direction to the direction of the induced magnetic field A from the current I to be measured flowing through the current line 11, and each of the first magnetic sensor 12a and the second magnetic sensor 12b. The main sensitivity axis directions are arranged in the same direction. In addition, the sub-sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are arranged in the same direction. The first magnetic sensor 12 a is arranged so that the back surface thereof faces the direction of the current line 11, and the second magnetic sensor 12 b is arranged so that the surface thereof faces the direction of the current line 11. Yes.

  In the current sensor 1 having the configuration shown in FIG. 9, the direction of the induced magnetic field A from the current I to be measured in which one main sensitivity axis direction of the first magnetic sensor 12 a and the second magnetic sensor 12 b flows through the current line 11. Since the other main sensitivity axis direction is directed in the opposite direction to the induced magnetic field A from the current I to be measured flowing through the current line 11, the influence of the induced magnetic field A is affected by the first magnetic sensor 12a. And appears as an output signal of substantially opposite phase from the second magnetic sensor 12b. Further, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b face the same direction, and the sub sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are the same. Since the direction is directed, the influence of the disturbance magnetic field appears equally in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the difference between the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy.

  FIG. 10 is a schematic diagram illustrating an example of a method for manufacturing the current sensor 1 according to the present embodiment. As shown in FIG. 10A, first, a first magnetic sensor 12a and a second magnetic sensor 12b are prepared. In FIG. 10A, the primary sensitivity axis direction of the first magnetic sensor 12a faces forward, and the secondary sensitivity axis direction faces right. In addition, the main sensitivity axis direction of the second magnetic sensor 12b faces forward, and the sub sensitivity axis direction faces right. That is, the first magnetic sensor 12a and the second magnetic sensor 12b have the same configuration, and the relationship between the angles formed by the main sensitivity axis direction and the sub sensitivity axis direction is the same. Here, the main surfaces on the upper side (GMR element side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The main surfaces on the lower side (substrate side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the back surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The relationship between the front and back may be reversed.

  Next, as shown in FIG. 10B, the first magnetic sensor 12a is arranged on the arrangement surface of the first circuit board 13a, and the second magnetic sensor 12b is arranged on the arrangement surface of the second circuit board 13b. . In the present embodiment, the first magnetic sensor 12a is arranged so that the surface of the first magnetic sensor 12a faces the arrangement surface of the first circuit board 13a, and the back surface of the second magnetic sensor 12b and the second magnetic sensor 12b are arranged. The second magnetic sensor 12b is arranged so as to face the arrangement surface of the circuit board 13b. As a result, as shown in FIG. 10B, the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b are both directed upward, and the first magnetic sensor 12a and the second magnetic sensor 12b When the respective primary sensitivity axis directions (arrows 14a and 14b) are directed in the same direction, the respective secondary sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other. Turn to the direction.

  Thereafter, as shown in FIG. 10C, the first circuit board 13a and the second circuit board 13b face each other with the current line 11 interposed therebetween so that the first circuit board 13a and the second circuit board 13b face each other. The circuit board 13a and the second circuit board 13b are arranged. Such an arrangement can be obtained, for example, by rotating the set of the first magnetic sensor 12a and the first circuit board 13a with respect to the set of the second magnetic sensor 12b and the second circuit board 13b. it can.

  In the current sensor 1 obtained by the method shown in FIG. 10, since the first magnetic sensor 12a and the second magnetic sensor 12b are arranged symmetrically with respect to the current line 11, the current line 11 and the first magnetic sensor are arranged. It becomes easy to make the distance to 12a and the distance between the current line 11 and the second magnetic sensor 12b uniform. Thereby, since a disturbance magnetic field can be canceled appropriately, the current measurement accuracy can be sufficiently increased. Moreover, since there is no circuit board between the current line 11 and the first magnetic sensor 12a and between the current line 11 and the second magnetic sensor 12b, the current line 11 and the first magnetic sensor 12a The distance and the distance between the current line 11 and the second magnetic sensor 12b can be reduced. For this reason, it is possible to increase the sensor output and sufficiently increase the current measurement accuracy.

  Further, since the same magnetic sensor can be used as the first magnetic sensor 12a and the second magnetic sensor 12b, it is easy to match the characteristics of the two magnetic sensors. For this reason, it is possible to cancel the influence of the disturbance magnetic field with high accuracy and to suppress the decrease in the current measurement accuracy.

  As described above, the current sensor 1 according to the present embodiment can reduce the influence of a disturbance magnetic field and suppress a decrease in current measurement accuracy. This is because in the current sensor 1 according to the present embodiment, the first magnetic sensor 12a and the second magnetic sensor 12b are arranged so that the sub-sensitivity axis direction faces a direction in which the disturbance magnetic field can be appropriately canceled. It is.

  9 and 10, the direction of the main sensitivity axis of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the current I to be measured flowing through the current line 11, and the main magnetic sensor 12b has a main direction. The case where the sensitivity axis direction is in the direction opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11 is taken as an example, but the configuration of the current sensor 1 according to the present embodiment is as follows. It is not limited to this. The direction of the main sensitivity axis of the first magnetic sensor 12a is opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the direction of the main sensitivity axis of the second magnetic sensor 12b is the current. The direction of the induced magnetic field A from the measured current I flowing through the line 11 may be directed.

  9 and 10, the configuration for canceling the disturbance magnetic field by taking the output difference has been described. However, the configuration of the current sensor 1 according to the present embodiment is not limited to this. A configuration may be adopted in which the disturbance magnetic field is canceled by taking the sum of outputs. In this case, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11 or the direction of the induced magnetic field. The sub-sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b may be opposite to each other.

  9 and 10, the current sensor 1 having the configuration in which the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b face each other with the current line 11 interposed therebetween is described. The configuration of the current sensor 1 according to the embodiment is not limited to this. A configuration may be adopted in which the surface opposite to the arrangement surface of the first circuit board 13a and the surface opposite to the arrangement surface of the second circuit board 13b face each other with the current line 11 interposed therebetween.

  In addition, this embodiment can be implemented in combination with any of the structures described in the other embodiments as appropriate.

(Embodiment 5)
In the present embodiment, another example of the current sensor 1 of the present invention will be described. FIG. 11 is a schematic diagram showing the current sensor 1 of the present embodiment. 11A is a perspective view schematically showing the configuration of the current sensor 1 and its periphery, and FIG. 11B is a plan view of the current sensor 1 as viewed from the lower left direction (front) of FIG. 11A.

  As shown in FIG. 11, the current sensor 1 according to the present embodiment includes a first magnetic sensor 12a and a second magnetic sensor 12b arranged around the current line 11, and includes the first magnetic sensor 12a. Includes a first circuit board 13a on which is disposed and a second circuit board 13b on which the second magnetic sensor 12b is disposed. The current sensor 1 includes an arithmetic device that calculates the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. In this respect, the current sensor 1 shown in FIG. 11 and the current sensor 1 shown in FIG. 1 are common. The difference between the current sensor 1 shown in FIG. 11 and the current sensor 1 shown in FIG. 1 is that the first magnetic sensor 12a and the second magnetic sensor 12b, and the first circuit board 13a and the second circuit board 13b. And the positional relationship. That is, in the current sensor 1 according to the present embodiment, the surface opposite to the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b face each other across the current line 11. Has been placed. In addition, magnetic sensors having the same configuration are used as the first magnetic sensor 12a and the second magnetic sensor 12b. Therefore, when the first magnetic sensor 12a and the second magnetic sensor 12b are viewed from the surface side, the angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction of the first magnetic sensor 12a, The angle formed by the auxiliary sensitivity axis direction with respect to the main sensitivity axis direction of the magnetic sensor 12b is substantially equal. Here, it is desirable that the first magnetic sensor 12a and the second magnetic sensor 12b include elements having the same structure manufactured using the same wafer. This is because in such a magnetic sensor, the sensitivity of the main sensitivity axis and the secondary sensitivity axis can be made equal, so that the influence of the disturbance magnetic field can be easily canceled.

  In the current sensor 1 shown in FIG. 11, the first magnetic sensor 12 a and the second magnetic sensor 12 b can obtain substantially reversed phase outputs by the induced magnetic field A from the current I to be measured flowing through the current line 11. As shown in FIG. More specifically, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the second magnetic sensor 12b The direction of the main sensitivity axis (arrow 14b) faces in the opposite direction to the direction of the induced magnetic field A from the current I to be measured flowing through the current line 11, and each of the first magnetic sensor 12a and the second magnetic sensor 12b. The main sensitivity axis directions are arranged in the same direction. In addition, the sub-sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are arranged in the same direction. The first magnetic sensor 12 a is arranged so that the back surface thereof faces the direction of the current line 11, and the second magnetic sensor 12 b is arranged so that the surface thereof faces the direction of the current line 11. Yes.

  In the current sensor 1 having the configuration shown in FIG. 11, the direction of the induced magnetic field A from the current I to be measured in which the main sensitivity axis direction of one of the first magnetic sensor 12 a and the second magnetic sensor 12 b flows through the current line 11. Since the other main sensitivity axis direction is directed in the opposite direction to the induced magnetic field A from the current I to be measured flowing through the current line 11, the influence of the induced magnetic field A is affected by the first magnetic sensor 12a. And appears as an output signal of substantially opposite phase from the second magnetic sensor 12b. Further, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b face the same direction, and the sub sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are the same. Since the direction is directed, the influence of the disturbance magnetic field appears equally in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the difference between the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy.

  FIG. 12 is a schematic diagram illustrating an example of a method for manufacturing the current sensor 1 according to the present embodiment. As shown in FIG. 12A, first, a first magnetic sensor 12a and a second magnetic sensor 12b are prepared. In FIG. 12A, the primary sensitivity axis direction of the first magnetic sensor 12a faces forward, and the secondary sensitivity axis direction faces right. In addition, the main sensitivity axis direction of the second magnetic sensor 12b faces forward, and the sub sensitivity axis direction faces right. That is, the first magnetic sensor 12a and the second magnetic sensor 12b have the same configuration, and the relationship between the angles formed by the main sensitivity axis direction and the sub sensitivity axis direction is the same. Here, the main surfaces on the upper side (GMR element side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The main surfaces on the lower side (substrate side) of the first magnetic sensor 12a and the second magnetic sensor 12b are the back surfaces of the first magnetic sensor 12a and the second magnetic sensor 12b, respectively. The relationship between the front and back may be reversed.

  Next, as shown in FIG. 12B, the first magnetic sensor 12a is arranged on the arrangement surface of the first circuit board 13a, and the second magnetic sensor 12b is arranged on the arrangement surface of the second circuit board 13b. . In the present embodiment, the first magnetic sensor 12a is arranged so that the back surface of the first magnetic sensor 12a faces the arrangement surface of the first circuit board 13a, and the back surface of the second magnetic sensor 12b and the second magnetic sensor 12b are arranged. The second magnetic sensor 12b is arranged so as to face the arrangement surface of the circuit board 13b. That is, the set of the first magnetic sensor 12a and the first circuit board 13a and the set of the second magnetic sensor 12b and the second circuit board 13b have the same configuration. For this reason, as shown in FIG. 12B, the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b both face upward, and the first magnetic sensor 12a and the second magnetic sensor 12b When the main sensitivity axis directions (arrows 14a and 14b) are directed in the same direction, the sub sensitivity axis directions (arrows 15a and 15b) of the first magnetic sensor 12a and the second magnetic sensor 12b are also the same direction. Turn to.

  Thereafter, as shown in FIG. 12C, the current line 11 is arranged so that the surface opposite to the arrangement surface of the first circuit board 13a and the arrangement surface of the second circuit board 13b face each other across the current line 11. The first circuit board 13 a and the second circuit board 13 b are arranged around the area 11.

  In the current sensor 1 obtained by the method shown in FIG. 12, a magnetic sensor having the same configuration can be used as the first magnetic sensor 12a and the second magnetic sensor 12b. Therefore, the characteristics of the two magnetic sensors can be matched. It becomes easy. For this reason, it is possible to cancel the influence of the disturbance magnetic field with high accuracy and to suppress the decrease in the current measurement accuracy. In addition, since the mounting pattern of the first magnetic sensor 12a on the first circuit board 13a is the same as the mounting pattern of the second magnetic sensor 12b on the second circuit board 13b, the magnetic sensor is mounted in the same process. A current sensor can be configured using the mounted circuit board. For this reason, it becomes possible to arrange the characteristics of the magnetic sensor and the circuit board at a low cost.

  FIG. 13 is a schematic diagram showing a modification of the current sensor 1 having the configuration shown in FIG. The basic configuration of the current sensor 1 shown in FIG. 13 is the same as that of the current sensor 1 shown in FIG. The difference between the current sensor 1 shown in FIG. 13 and the current sensor 1 shown in FIG. That is, in the current sensor 1 shown in FIG. 13, the spacer 17 is disposed between the current line 11 and the second circuit board 13b. By arranging the spacers 17 in this way, the distance between the current line 11 and the first magnetic sensor 12a and the distance between the current line 11 and the second magnetic sensor 12b can be easily made uniform. For this reason, it is possible to sufficiently improve the current measurement accuracy.

  13 shows a configuration in which the spacer 17 is disposed between the current line 11 and the second circuit board 13b, the spacer 17 is disposed between the current line 11 and the second magnetic sensor 12b. May be. Further, another spacer may be disposed between the current line 11 and the first circuit board 13a (or the first magnetic sensor 12a).

  As described above, the current sensor 1 according to the present embodiment can reduce the influence of a disturbance magnetic field and suppress a decrease in current measurement accuracy. This is because in the current sensor 1 according to the present embodiment, the first magnetic sensor 12a and the second magnetic sensor 12b are arranged so that the sub-sensitivity axis direction faces a direction in which the disturbance magnetic field can be appropriately canceled. It is.

  11 to 13, the main sensitivity axis direction of the first magnetic sensor 12a faces the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the main magnetic sensor 12b has a main sensitivity axis direction. The case where the sensitivity axis direction is in the direction opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11 is taken as an example, but the configuration of the current sensor 1 according to the present embodiment is as follows. It is not limited to this. The direction of the main sensitivity axis of the first magnetic sensor 12a is opposite to the direction of the induced magnetic field A from the measured current I flowing through the current line 11, and the direction of the main sensitivity axis of the second magnetic sensor 12b is the current. The direction of the induced magnetic field A from the measured current I flowing through the line 11 may be directed.

  11 to 13, the configuration for canceling the disturbance magnetic field by taking the output difference has been described. However, the configuration of the current sensor 1 according to the present embodiment is not limited thereto. A configuration may be adopted in which the disturbance magnetic field is canceled by taking the sum of outputs. In this case, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are both the direction of the induced magnetic field A from the measured current I flowing through the current line 11 or the direction of the induced magnetic field A. It suffices that the sub-sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b are opposite to each other in opposite directions.

  In addition, this embodiment can be implemented in combination with any of the structures described in the other embodiments as appropriate.

(Embodiment 6)
In the present embodiment, another example of the current sensor 1 of the present invention will be described. The current sensor 1 according to the present embodiment is the same as the current sensor 1 described in the first to fifth embodiments, except that the first magnetic sensor 12a and the second magnetic sensor 12b are magnetoresistive elements. Is equivalent to the one applied.

  The first magnetic sensor 12a and the second magnetic sensor 12b according to the present embodiment are a magnetic proportional sensor or a magnetic balanced sensor. The magnetic proportional sensor is configured to include, for example, a bridge circuit including two magnetoresistive elements and two fixed resistance elements that are magnetic sensor elements. In addition, the magnetic balance sensor is, for example, a bridge circuit composed of two magnetoresistive elements and two fixed resistance elements that are magnetic sensor elements, and a magnetic field in a direction that cancels the magnetic field generated by the current to be measured. And a feedback coil. When the magnetic proportional sensor is employed, the configuration relating to the feedback coil and the control thereof, such as the magnetic balance sensor, is not required, so that the configuration can be simplified and the current sensor can be reduced in size. On the other hand, when a magnetic balance sensor is employed, a current sensor having a high response speed and a small temperature dependence can be easily realized.

  The magnetoresistive effect element used for the first magnetic sensor 12a and the second magnetic sensor 12b includes a GMR (Giant Magneto Resistance) element, a TMR (Tunnel Magneto Resistance) element, and the like, but here, it is orthogonal to the sensitivity axis. A GMR element having sensitivity also in the direction to be used is used. A magnetoresistive effect element such as a GMR element has a property that the resistance value is changed by applying an induced magnetic field from a current to be measured, and this is used for the first magnetic sensor 12a and the second magnetic sensor 12b. Thus, the magnitude of the induced magnetic field can be detected.

  It is desirable that the first magnetic sensor 12a and the second magnetic sensor 12b include elements having the same structure manufactured using the same wafer. This is because in such a magnetic sensor, the sensitivities of the main sensitivity axis and the sub-sensitivity axis can be made equal, so that the influence of the disturbance magnetic field can be canceled sufficiently and a decrease in current measurement accuracy can be suppressed.

  FIG. 14 is a schematic diagram showing the structure of a GMR element used for the first magnetic sensor 12a and the second magnetic sensor 12b. FIG. 14A shows a cross-sectional structure, and FIG. 14B shows a planar structure. As shown in FIG. 14A, the GMR element has a laminated structure of a plurality of films provided on the substrate 101. That is, the GMR element includes a seed layer 102, a first ferromagnetic film 103, an antiparallel coupling film 104, a second ferromagnetic film 105, a nonmagnetic intermediate layer 106, a soft magnetic free layer (free magnetic layer) 107, and A protective layer 108 is included. Further, as shown in FIG. 14B, it has a shape (a meander shape) formed by folding a plurality of strip-like long patterns (stripes) arranged so that their longitudinal directions are parallel to each other.

  In this GMR element, the first ferromagnetic film 103 and the second ferromagnetic film 105 are antiferromagnetically coupled via the antiparallel coupling film 104, and a so-called self-pinned type ferromagnetic fixed layer. (SFP layer: Synthetic Ferri Pinned layer) is configured. As described above, the GMR element shown in FIG. 14 is a spin valve type element using the ferromagnetic fixed layer, the nonmagnetic intermediate layer 106 and the soft magnetic free layer 107. In FIG. 14, for simplicity of explanation, the base layer other than the GMR element is omitted, but, for example, between the substrate 101 and the seed layer 102, for example, Ta, Hf, Nb, Zr, Ti, An underlayer composed of a nonmagnetic material containing at least one element of Mo, W, or the like may be provided.

  The seed layer 102 is made of NiFeCr or Cr. The first ferromagnetic film 103 is preferably made of a CoFe alloy containing 40 atomic% to 80 atomic% of Fe. This is because the CoFe alloy having this composition range has a large coercive force and can stably maintain the magnetization against an external magnetic field. The first ferromagnetic film 103 applies a magnetic field in the direction perpendicular to the longitudinal direction of the meander shape (the direction from the back side to the near side in FIG. 14A and the direction from the top side to the bottom side in FIG. 14B) during the film formation. As a result, induced magnetic anisotropy is imparted. The antiparallel coupling film 104 is made of Ru or the like. The second ferromagnetic film 105 is preferably made of a CoFe alloy containing 0 atomic% to 40 atomic% of Fe. This is because a CoFe alloy having this composition range has a small coercive force, and is easily magnetized in an antiparallel direction (a direction different by 180 °) with respect to the direction in which the first ferromagnetic film 103 is preferentially magnetized. is there. The second ferromagnetic film 105 is applied with a magnetic field (magnetic field perpendicular to the longitudinal direction of the meander shape) applied during the film formation, similar to that during the film formation of the first ferromagnetic film 103. Induced magnetic anisotropy is imparted. By forming the film while applying such a magnetic field, the first ferromagnetic film 103 is preferentially magnetized in the direction of the applied magnetic field (hereinafter referred to as Pin1 direction), and the second ferromagnetic film 105 is Magnetization is performed in an antiparallel direction (a direction different by 180 °, hereinafter referred to as Pin2 direction) from the magnetization direction of the ferromagnetic film 103. The nonmagnetic intermediate layer 106 is made of Cu or the like.

  The soft magnetic free layer (free layer) 107 is made of a magnetic material such as a CoFe alloy, a NiFe alloy, or a CoFeNi alloy. During the formation of the soft magnetic free layer 107, a meander-shaped magnetic field in the longitudinal direction (the direction perpendicular to the Pin 2 direction, the X-axis direction) is applied, and induced magnetic anisotropy is applied to the soft magnetic free layer 107 after the film formation. It is preferable that the property is imparted. Thereby, it is possible to obtain a GMR element in which resistance is linearly changed with respect to the external magnetic field in the X-axis direction and the hysteresis is small. The protective layer 108 is made of Ta, Ru, or the like.

  The GMR element has a hard bias layer 109, and it is preferable that a constant magnetic field is applied from the hard bias layer 109 to the soft magnetic free layer (free layer) 107. The direction of the magnetic field (hereinafter, hard bias (HB)) by the hard bias layer 109 is the meander-shaped longitudinal direction (direction perpendicular to the Pin2 direction, X-axis direction). Such a hard bias layer 109 can increase the sensitivity of the GMR element.

  Also, the hard bias layer 109 controls the sensitivity axis of the GMR element to be in a direction perpendicular to the direction of the hard bias, and the secondary sensitivity axis to be in the direction of the hard bias. Therefore, by utilizing this, it is possible to realize a configuration in which the direction of the hard bias of the GMR element used in the current sensor is aligned and the influence of the disturbance magnetic field appearing in the sub-sensitivity axis direction can be canceled appropriately. Specifically, in the current sensor that takes the difference in output, the direction of the hard bias of the GMR element so that the secondary sensitivity axis of the first magnetic sensor 12a and the secondary sensitivity axis of the second magnetic sensor 12b are in the same direction. To control. In the current sensor that takes the sum of outputs, the direction of the hard bias is controlled so that the auxiliary sensitivity axis of the first magnetic sensor 12a and the auxiliary sensitivity axis of the second magnetic sensor 12b are directed in opposite directions. Thereby, the influence of a disturbance magnetic field can be reduced and the fall of a current measurement precision can be suppressed.

  In the above-described GMR element and the magnetic sensor including the GMR element, the main sensitivity axis direction is the Pin2 direction. The sub-sensitivity axis direction is a direction perpendicular to Pin2. There is no substantial sensitivity in the direction perpendicular to the membrane.

  FIG. 15 is a graph showing the resistance value of the GMR element (that is, the sensitivity of the GMR element) when a magnetic field is applied in the sub-sensitivity axis direction of the GMR element. In FIG. 15, the horizontal axis represents the magnitude of the applied magnetic field in the sub-sensitivity axis direction (that is, the hard bias direction). When the applied magnetic field is expressed as negative, it indicates that a magnetic field in the hard bias direction is applied, and when the applied magnetic field is expressed as positive, it indicates that a magnetic field in the direction opposite to the hard bias direction is applied. The vertical axis represents the resistance value of the GMR element. A solid line indicates the characteristics of the first GMR element, and a broken line indicates the characteristics of the second GMR element.

  15A shows characteristics when the hard bias is very weak, FIG. 15B shows characteristics when the hard bias is strong, and FIG. 15C shows characteristics when the hard bias is very strong. When the hard bias is weak as shown in FIG. 15A, the sensitivity characteristics in the sub-sensitivity axis direction of the two GMR elements are greatly different. The resistance value of the first GMR element decreases when a negative magnetic field is applied, whereas the resistance value of the second GMR element decreases when a positive magnetic field is applied. This means that the sub-sensitivity axes are not aligned. In this case, it is difficult to cancel the influence of the disturbance magnetic field appearing in the auxiliary sensitivity axis direction with high accuracy. On the other hand, when the hard bias is strong as shown in FIGS. 15B and 15C, the sensitivity characteristics in the sub-sensitivity axis direction of the two GMR elements are aligned. In this case, the influence of the disturbance magnetic field appearing in the auxiliary sensitivity axis direction can be canceled with high accuracy.

  As described above, when the magnetic sensor using the magnetoresistive effect element is applied to the first magnetic sensor 12a and the second magnetic sensor 12b, the sub sensitivity axis is controlled by controlling the sensitivity characteristic in the sub sensitivity axis direction by the hard bias. It becomes possible to cancel the influence of the disturbance magnetic field appearing in the direction with high accuracy. For this reason, it is possible to suppress a decrease in current measurement accuracy.

  This embodiment can be implemented in appropriate combination with the structures described in the other embodiments.

(Embodiment 7)
In the present embodiment, another example of the current sensor 1 of the present invention will be described. FIG. 16 is a schematic diagram illustrating an example of the current sensor 1 according to the present embodiment. 16A is a perspective view schematically showing the configuration of the current sensor 1 and its periphery, FIG. 16B is a plan view of the current sensor 1 as viewed from above FIG. 16A, and FIG. 16C is a main sensitivity axis of the magnetic sensor. It is a schematic diagram which shows the relationship between a direction and an auxiliary sensitivity axis direction, and the direction of an induction magnetic field. FIG. 17 is a schematic diagram showing another example of the current sensor 1 of the present embodiment. 17A is a perspective view schematically showing the configuration of the current sensor 1 and its periphery, FIG. 17B is a plan view of the current sensor 1 as viewed from above FIG. 17A, and FIG. 17C is the main sensitivity axis of the magnetic sensor. It is a schematic diagram which shows the relationship between a direction and an auxiliary sensitivity axis direction, and the direction of an induction magnetic field.

  As shown in FIGS. 16 and 17, the basic configuration of the current sensor 1 according to the present embodiment is common to the configuration of the current sensor 1 according to the first to sixth embodiments. On the other hand, the current sensor 1 according to the present embodiment relates to the first to sixth embodiments in that the main sensitivity axis direction (arrows 14a and 14b) does not face the direction parallel to the induced magnetic field A. This is different from the current sensor 1.

The current sensor 1 shown in FIG. 16 has a configuration in which the first magnetic sensor 12a and the second magnetic sensor 12b of the current sensor shown in FIG. 1 are rotated by a predetermined angle about an axis perpendicular to the arrangement surface. (See FIGS. 16A and 16B). Specifically, as illustrated in FIG. 16C, the current sensor 1 is configured so that the main sensitivity axis directions of the first magnetic sensor 12 a and the second magnetic sensor 12 b form an angle θ ₁ with respect to the induced magnetic field A. It is configured. In other words, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces a direction that is not parallel to the induced magnetic field A from the current I to be measured flowing through the current line 11, and the second The direction of the main sensitivity axis of the magnetic sensor 12b (arrow 14b) is directed in a direction that is not parallel to the direction of the induced magnetic field A from the measured current I flowing through the current line 11. However, like the first to sixth embodiments, the main sensitivity axis direction and the direction of the induced magnetic field A are not orthogonal so that the current sensor 1 has sensitivity to the induced magnetic field A. That is, θ ₁ ≠ 90 ° × n (n is an integer) is satisfied.

In the current sensor 1 of the present embodiment in which the main sensitivity axis direction and the induced magnetic field A form a predetermined angle, the main sensitivity axis direction component of the induced magnetic field A is detected. In the angle between the direction of the induced magnetic field A and the main sensitivity axis direction theta _1, the intensity of the induced magnetic field A is if H _A, the magnetic field by the first magnetic sensor 12a and the second magnetic sensor 12b receives each The strength H is H _A cos θ ₁ (<H _A ). In other words, the main sensitivity axis direction, since it is arranged such that the angle theta ₁ inclined with respect to the direction of the induced magnetic field A, the intensity H of the magnetic field by the first magnetic sensor 12a and the second magnetic sensor 12b receives each The strength of the induction magnetic field A becomes smaller than _HA . Therefore, the intensity of the magnetic field by the first magnetic sensor 12a and the second magnetic sensor 12b receives by adjusting the angle theta _1, can be adjusted a measurable range of the current sensor 1.

  In the current sensor 1 shown in FIG. 16, the main sensitivity axis directions of the first magnetic sensor 12a and the second magnetic sensor 12b face the same direction, and the first magnetic sensor 12a and the second magnetic sensor 12b are in the same direction. Since the sub-sensitivity axis directions of the sensors 12b are in the same direction, the influence of the disturbance magnetic field appears equally in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the difference between the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy.

The current sensor 1 shown in FIG. 17 has the first magnetic sensor 12a and the second magnetic sensor 12b of the current sensor shown in FIG. 5 at a predetermined angle on the arrangement surface of the first circuit board 13a and the second circuit board 13b. It has a rotated configuration (see FIGS. 17A and 17B). Specifically, as shown in FIG. 17C, the current sensor 1, as the main sensitivity axis of the first magnetic sensor 12a and the second magnetic sensor 12b is at an angle theta ₂ with respect to the induced magnetic field A It is configured. In other words, the main sensitivity axis direction (arrow 14a) of the first magnetic sensor 12a faces a direction that is not parallel to the induced magnetic field A from the current I to be measured flowing through the current line 11, and the second The direction of the main sensitivity axis of the magnetic sensor 12b (arrow 14b) is directed in a direction that is not parallel to the direction of the induced magnetic field A from the measured current I flowing through the current line 11. However, like the first to sixth embodiments, the main sensitivity axis direction and the direction of the induced magnetic field A are not orthogonal so that the current sensor 1 has sensitivity to the induced magnetic field A. That is, θ ₂ ≠ 90 ° × n (n is an integer) is satisfied. In this current sensor 1, the intensity of the magnetic field by the first magnetic sensor 12a and the second magnetic sensor 12b receives by adjusting the angle theta _2, can adjust the measurable range of the current sensor 1.

  In the current sensor 1 shown in FIG. 17, the main sensitivity axis directions of the first magnetic sensor 12 a and the second magnetic sensor 12 b are opposite to each other, and the first magnetic sensor 12 a and the second magnetic sensor 12 b are opposite to each other. Since the sub-sensitivity axis directions of the magnetic sensors 12b are opposite to each other, the influence of the disturbance magnetic field appears in reverse in the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b. For this reason, by taking the sum of the output of the first magnetic sensor 12a and the output of the second magnetic sensor 12b, it is possible to sufficiently reduce the influence of the disturbance magnetic field and suppress the decrease in the current measurement accuracy.

  As described above, the current sensor 1 according to the present embodiment is configured such that the main sensitivity axis direction and the induced magnetic field A form a predetermined angle. By adjusting this angle, the current sensor 1 The measurable range can be adjusted. For example, the sensitivity can be made lower than that of the current sensor 1 of the first to sixth embodiments, which is arranged so that the main sensitivity axis direction is parallel to the direction of the induced magnetic field A, and the measurable range is widened. Can do.

  In the present embodiment, the first magnetic sensor 12a and the second magnetic sensor 12b are rotated so that the direction of the induced magnetic field A and the main sensitivity axis direction form a predetermined angle. The circuit board 13a and the second circuit board 13b may be rotated. Further, the first circuit board 13a and the second circuit board 13b (or the first magnetic sensor 12a and the second magnetic sensor 12b) are rotated so that the auxiliary sensitivity axis is not affected by the induced magnetic field A. Thus, the sub-sensitivity axis direction with respect to the induced magnetic field A may be controlled. In this case, for example, by making the auxiliary sensitivity axis direction orthogonal to the induced magnetic field A, the influence of the induced magnetic field A on the auxiliary sensitivity axis can be suppressed.

  In addition, this embodiment can be implemented in combination with any of the structures described in the other embodiments as appropriate.

  As described above, the current sensor 1 of the present invention can sufficiently cancel the disturbance magnetic field by controlling the sub-sensitivity axis direction in addition to the main sensitivity axis direction. Thereby, the fall of the current measurement precision can be suppressed.

  In addition, this invention is not limited to the said embodiment, A various change can be implemented. For example, the arrangement and size of each component in the above embodiment can be changed as appropriate. Further, the direction of the current I to be measured flowing through the current line 11 can be reversed. In addition, the structures described in Embodiments 1 to 7 can be implemented in appropriate combination. In addition, the present invention can be implemented with appropriate modifications without departing from the scope of the present invention.

  The current sensor of the present invention can be used, for example, to detect the magnitude of a current for driving a motor of an electric vehicle or a hybrid car.

  This application is based on Japanese Patent Application No. 2011-045475 of application on March 2, 2011. All this content is included here.

Claims (19)

A first magnetic sensor that is disposed around a current line through which a current to be measured flows, detects an induced magnetic field caused by the current flowing through the current line, and has a secondary sensitivity axis in a direction perpendicular to the main sensitivity axis; Comprising a second magnetic sensor;
The first magnetic sensor and the second magnetic sensor are disposed across the current line,
The main sensitivity axis direction of the first magnetic sensor faces a direction not orthogonal to the direction of the induced magnetic field from the current flowing through the current line, and the main sensitivity axis direction of the second magnetic sensor passes through the current line. It is arranged to face a direction that is not orthogonal to the direction of the induced magnetic field from the flowing current,
The primary sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are in the same direction, and the secondary sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are in the same direction. Or the respective main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are opposite to each other, and the first magnetic sensor and the second magnetic sensor A current sensor, wherein each sub-sensitivity axis direction is disposed in the opposite direction. The main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are in the same direction,
2. The current sensor according to claim 1, further comprising an arithmetic unit that calculates a difference between an output of the first magnetic sensor and an output of the second magnetic sensor. The main sensitivity axis directions of the first magnetic sensor and the second magnetic sensor are opposite to each other,
The current sensor according to claim 1, further comprising an arithmetic unit that calculates a sum of an output of the first magnetic sensor and an output of the second magnetic sensor. A first circuit board on which the first magnetic sensor is arranged on the arrangement surface;
A second circuit board on which the second magnetic sensor is arranged on the arrangement surface,
4. The device according to claim 1, wherein the arrangement surface of the first circuit board and the arrangement surface of the second circuit board are arranged so as to face each other with the current line interposed therebetween. 5. The current sensor described. A first circuit board on which the first magnetic sensor is arranged on the arrangement surface;
A second circuit board on which the second magnetic sensor is arranged on the arrangement surface,
The surface of the first circuit board opposite to the arrangement surface and the surface of the second circuit board opposite to the arrangement surface are arranged so as to face each other across the current line. The current sensor according to any one of claims 1 to 3.   The main sensitivity axis direction and sub-sensitivity axis direction of the first magnetic sensor and the main sensitivity axis direction and sub-sensitivity axis direction of the second magnetic sensor have a mirror image relationship. Current sensor.   6. The primary sensitivity axis direction and the secondary sensitivity axis direction of the first magnetic sensor and the primary sensitivity axis direction and the secondary sensitivity axis direction of the second magnetic sensor have a mirror image relationship. Current sensor. When the first magnetic sensor and the second magnetic sensor are viewed from the surface side, an angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction of the first magnetic sensor, and the second magnetic sensor The angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction is equal to
The first magnetic sensor is disposed on the first circuit board such that the surface thereof faces the arrangement surface of the first circuit board;
5. The current sensor according to claim 4, wherein the second magnetic sensor is disposed on the second circuit board such that a back surface thereof faces an arrangement surface of the second circuit board. 6. When the first magnetic sensor and the second magnetic sensor are viewed from the surface side, an angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction of the first magnetic sensor, and the second magnetic sensor The angle formed by the sub-sensitivity axis direction with respect to the main sensitivity axis direction is equal to
The first magnetic sensor is disposed on the first circuit board such that the surface thereof faces the arrangement surface of the first circuit board;
6. The current sensor according to claim 5, wherein the second magnetic sensor is disposed on the second circuit board such that a back surface thereof faces an arrangement surface of the second circuit board. A first circuit board on which a first magnetic sensor is arranged on an arrangement surface;
A second circuit board on which a second magnetic sensor is arranged on the arrangement surface,
2. The device according to claim 1, wherein the arrangement surface of the first circuit board and the surface of the second circuit board opposite to the arrangement surface are arranged so as to face each other across the current line. 4. The current sensor according to any one of 3.   By disposing a spacer between the current line and the first magnetic sensor or between the current line and the first circuit board, a distance between the current line and the first magnetic sensor and The current sensor according to claim 10, wherein the distance between the current line and the second magnetic sensor is equal.   The current sensor according to claim 8, wherein the first magnetic sensor and the second magnetic sensor are elements having the same structure manufactured using the same wafer.   The current sensor according to claim 9, wherein the first magnetic sensor and the second magnetic sensor are elements having the same structure manufactured using the same wafer.   The current sensor according to claim 10, wherein the first magnetic sensor and the second magnetic sensor are elements having the same structure manufactured using the same wafer.   The current sensor according to claim 11, wherein the first magnetic sensor and the second magnetic sensor are elements having the same structure manufactured using the same wafer. The first magnetic sensor and the second magnetic sensor are magnetic sensors using magnetoresistive elements,
The sub-sensitivity axis direction of the first magnetic sensor and the sub-sensitivity axis direction of the second magnetic sensor are directions of a hard bias of the magnetoresistive effect element respectively included in the first magnetic sensor. Item 16. The current sensor according to any one of Items 15.   The current sensor according to any one of claims 1 to 11, wherein the first magnetic sensor and the second magnetic sensor are magnetic sensors using Hall elements having a magnetic converging plate.   The main sensitivity axis direction of the first magnetic sensor faces a direction parallel to the induced magnetic field from the current flowing through the current line, and the main sensitivity axis direction of the second magnetic sensor flows through the current line. The current sensor according to any one of claims 1 to 17, wherein the current sensor is directed in a direction parallel to a direction of an induced magnetic field from the current.   The main sensitivity axis direction of the first magnetic sensor faces a direction not parallel to the induced magnetic field from the current flowing through the current line, and the main sensitivity axis direction of the second magnetic sensor flows through the current line. The current sensor according to any one of claims 1 to 17, wherein the current sensor is directed in a direction that is not parallel to a direction of an induced magnetic field from a current to be generated.

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